\tracingonline=2
\tracingcommands=2
\tracingmacros=2
\tracingrestores=2

\catcode`{=1
\catcode`}=2
\catcode`#=6

\expandafter \let \csname x\endcsname = \count
\show\x

\expandafter \global \expandafter \let \csname y\endcsname = \count
\show\y

\iftrue \expandafter \relax \else \show \x \fi

\def\testmacrox{\testmacroa}
\def\testmacroy{\testmacrob}
\def\testmacroz{\testmacroc}
\def\testmacrozz{\testmacrocc}
\def\testmacroa{aa}
\def\testmacrob{bb}
\def\testmacroc{cc}
\def\testmacrocc{ccc}
\immediate\write16{}
\expandafter \testmacrox \testmacroy \testmacroz \testmacrozz

\immediate\write16{}
\expandafter \expandafter \testmacrox \testmacroy \testmacroz \testmacrozz

% expandafter and if
\def\two#1#2{}
\expandafter\two\ifx1134\fi78
\expandafter\two\ifx1234\fi78
\expandafter\two\ifx1234\else56\fi78
\ifx11 \expandafter\two \fi78
\ifx11 \expandafter\two \else34\fi78

\end


